Initial backup of LTP-305G matrix clock setup on matrixpi

Captures everything needed to redeploy the two-display clock (hour on I2C
0x61, minute on I2C 0x63) on a fresh Pi:

- Both systemd units (matrix0x61.service, matrix0x63.service)
- Deployed Pimoroni script tree, including the local %I (12-hour) clock
  customization
- Vendored upstream sources (ltp305-python, breakout-garden) so restore is
  fully offline-capable
- Boot config snippet enabling I2C
- install.sh that wires it all back up idempotently
- Inventory doc cross-referencing every live-system path

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

vendor/breakout-garden/examples/heartbeat/heartbeat.py

@@ -0,0 +1,133 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+# NOTE! This code should not be used for medical diagnosis. It's
+# for fun/novelty use only, so bear that in mind while using it.
+
+import sys
+import time
+
+from PIL import Image
+from PIL import ImageFont
+from PIL import ImageDraw
+
+from threading import Thread
+from luma.core.interface.serial import spi
+from luma.oled.device import sh1106
+
+from max30105 import MAX30105, HeartRate
+
+print("""
+NOTE! This code should not be used for medical diagnosis. It's
+for fun/novelty use only, so bear that in mind while using it.
+
+This Pimoroni Breakout Garden example requires a
+MAX30105 Breakout and a 1.12" OLED Breakout (SPI).
+
+The Pulse-O-Matic 6000 is a heartbeat plotter and BPM display.
+
+Press Ctrl+C a couple times to exit.
+""")
+
+# Set up OLED
+oled = sh1106(spi(port=0, device=1, gpio_DC=9), rotate=2, height=128, width=128)
+
+# Load fonts
+lsb_18 = ImageFont.truetype("fonts/LiberationSans-Bold.ttf", 18)
+lsr_12 = ImageFont.truetype("fonts/LiberationSans-Regular.ttf", 12)
+
+# Set up MAX30105 Breakout
+max30105 = MAX30105()
+max30105.setup(leds_enable=2)
+
+max30105.set_led_pulse_amplitude(1, 0.2)
+max30105.set_led_pulse_amplitude(2, 12.5)
+max30105.set_led_pulse_amplitude(3, 0)
+
+max30105.set_slot_mode(1, 'red')
+max30105.set_slot_mode(2, 'ir')
+max30105.set_slot_mode(3, 'off')
+max30105.set_slot_mode(4, 'off')
+
+hr = HeartRate(max30105)
+data = []
+running = True
+
+bpm = 0
+bpm_avg = 0
+beat_detected = False
+beat_status = False
+
+
+def sample():
+    """Function to thread heartbeat values separately to
+ OLED drawing"""
+    global bpm, bpm_avg, beat_detected, beat_status
+
+    average_over = 5
+    bpm_vals = [0 for x in range(average_over)]
+    last_beat = time.time()
+
+    while running:
+        t = time.time()
+        samples = max30105.get_samples()
+        if samples is not None:
+            for i in range(0, len(samples), 2):
+                ir = samples[i + 1]
+                beat_detected = hr.check_for_beat(ir)
+                if beat_detected:
+                    beat_status = True
+                    delta = t - last_beat
+                    last_beat = t
+                    bpm = 60 / delta
+                    bpm_vals = bpm_vals[1:] + [bpm]
+                    bpm_avg = sum(bpm_vals) / average_over
+                d = hr.low_pass_fir(ir & 0xff)
+                data.append(d)
+                if len(data) > 128:
+                    data.pop(0)
+
+        time.sleep(0.05)
+
+
+# The thread to measure acclerometer values
+t = Thread(target=sample)
+t.start()
+
+# The main loop that draws values to the OLED
+while True:
+    try:
+        img = Image.open("images/heartbeat.png").convert(oled.mode)
+        draw = ImageDraw.Draw(img)
+
+        # Draw the heartbeat trace
+        vals = data
+        new_vals = [x / float((max(vals) - min(vals))) * 32 for x in vals]
+
+        for i in range(1, len(new_vals)):
+            draw.line([(i - 1, 80 - new_vals[i - 1]), (i, 80 - new_vals[i])],
+                      fill="white")
+
+        # Draw the Pulse-O-Matic "branding"
+        draw.rectangle([(0, 0), (128, 20)], fill="black")
+        if bpm_avg > 40:
+            draw.text((0, 1), "BPM: {:.2f}".format(bpm_avg), fill="white",
+                      font=lsb_18)
+        else:
+            draw.text((0, 1), "BPM: --.--", fill="white", font=lsb_18)
+        if beat_status:
+            draw.text((115, 1), u"\u2665", fill="white", font=lsb_18)
+            beat_status = False
+        draw.line([(0, 20), (128, 20)], fill="white")
+
+        draw.rectangle([(0, 108), (128, 128)], fill="black")
+        draw.text((0, 110), "Pulse-O-Matic 6000", fill="white", font=lsr_12)
+        draw.line([(0, 108), (128, 108)], fill="white")
+
+        # Display on the OLED
+        oled.display(img)
+    except ZeroDivisionError:
+        pass
+    except KeyboardInterrupt:
+        running = False
+        sys.exit(0)